Electromagnetic relay



Oct. 6, 1959 B. s. BENGTssoN ELECTROMAGNE'I'IC RELAY Filed March 1o,195e /IG 3 34 312@ 20 54 /f' /2 FIG. 5 45a, ,50

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n /NVENTOR BERT/L S. E/VGTSSON A TPNEYS United States Patent OELECTROMAGNETIC RELAY Bertil S. Bengtsson, New Britain, Conn., assignorto The Hart Manufacturing Company, Hartford, Conn., a corporation ofConnecticut Application March 10, '1958, Serial No. 720,333

1-1 claims. (c1. zoo- 104) This invention relates to electromagneticrelays, and more particularly toA improved and novel structure forbiasing the contact carrier of such a relay in a manner to gain greaterdependability and life with reduction in the cost of manufacture.

A primary object is to provide novel means for transversely biasing thecontact carrier of a relay armature to effect a more uniform applicationof tension to the contact carrier than has heretofore been obtained withthe leaf or coil springs commonly employed for that purpose.

A further object is to provide an improved contact carrier biasingspring which reduces, by damping out, undesirable carrier oscillationsintroduced by coil type biasing springs.

Other objects are to reduce the number of required parts in a relayassembly; to simplify fabrication of the housing-like supportingstructure in a manner to utilize portions thereof as the sole fasteningmeans for the parts housed thereby; to permit assembly of the devicewithout the use'of screws or rivets; to permit installation, removal andreplacement of the tensioning spring or springs without completedisassembly of Ithe cooperating components; and to insure greaterdependability and longer spring life than has heretofore been obtainedin relay switches ofthis general type.

Other objects will be in part obvious, and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements and arrangement of parts which will beexemplified in the construction hereafter set forth, fthe scope of theapplication of which will be indicated in the appended claims.

lIn the drawings: l

Fig. l is a vertical section of an assembled solenoid operated multiplecontact relay switch incorporating the invention.

fFig. 2 is a plan View of the base portion of the switch of Fig. 1 withthe cover and solenoid removed to show the contact and contact carrierassembly. v

Fig. 3 is a sectional view taken along lines 3 3 o Fig. 2.

Fig. 4 is la sectional view taken along line 4 4 of Fig. 2.

IFig. 5 is a View similarfto that of Fig. 2, showing nonsymmetricalbiasing of fthe contact carrier to obtain sequential operation of thecontacts with one set of contacts opening and then closing prior tocorresponding action of the other set.

Fig. 6 is a section along line 6 6 of Fig. 5.

The drawings disclose the invention as embodied in a solenoid operatedrelay switch 10 comprising a chambered base 11 of insulating material inwhich a spring biased contact carrier is slidably mounted to actuate apair vof switch contact connecting bars, one at each end of the carrier,with each bar having circuit controlling end portions operativelydisposed between paired contacts. A cover 12 is pressed t to base 11 andprovides v that as carrier 31 moves downwardly support for an actuatingsolenoid 13 mounted therein to depend from the top wall of cover 12. Atop pole piece 14 is clamped between the top wall of cover 12 and anelectromagnetic coil 17 of solenoid 13, with a lower pole piece 15 andinsulating spacer 16 supported on the top of base 11. The pressed fitrelation between cover 12 and base 11 maintains lower pole piece 15 andspacer 16 rmly clamped between the lower end of coil 17 and the topsurfaces of base 11, proper alignment being insured by snug tit of thoseparts with cover 12.

Solenoid 113 is of known construction with the windings of coil 17encircling a metallic center-bored core 18 having an upper integraltubular portion riveted marginally of an aperture in cover .12. Anarmature 20 of magnetic material is mounted on a brass shaft 22, bossedat 23 for slidable engagement in the bore of core 18, with a smallerboss 24 about which the lower end of a helical spring 25 tits, the upperend of spring 25 being adjustably positioned by screw 28. Armature 20has a carrier contacting plunger 26 mounted axially to depend therefrom,a shading coil 29 being provided in core 18 if re-l quired for AJC.operation. Carrier 31 is urged upwardly toward plunger .26 by one ormore wire-like springs 45, 46, as more fully described below, thetension of spring 25 being suliicient, with solenoid 13 de-energized toovercome said upward carrier bias and force carrier 31 and a pair ofconnected contact bars 32 downward to a lower switch closing position.Energization of solenoid 13 results in armature 20 being retracted tothe position shown in Figs. 1 and 2 to further compress spring 25,removing Ithe downward bias on carrier 31 through armature 20 to allowthe urge of the wire-like springs to return the carrier and contact barsto an upper switch closing position.

Base 11 may be a plastic die casting or the like, in the form of anupwardly open housing in which circuit-controlling mechanism associatedwith carrier 31 operates in response to energization or de-energizationof solenoid 13. The various elements comprising that mechanisrn aresecurely fastened to base portions or supported thereby without use ofscrews or rivets, with spaced terminal strips 34a, 35a supporting pairedcontact points 34 and 35, preferably moulded integrally therewith toextend through the bottom base Wall. Referring to Figs. 2 and 3, carrier31 is slidably mounted in a vertical plane with a contact bar 32connected to each end thereof for alternate circuit closing engagementwith upper contacts 34 or lower contacts 35. Like paired contacts areassociated with each bar 32, hence each bar controls opening or closingof two separate circuits in response to solenoid action. Bars 32 arepositioned in slots 36 at each end of carrier 31 and laterally notchedat 33 for locked engagement with carrier 31.

As best shown in Figs. 2 and 3, a pair of wire-like spring elements 45and 46 are disposed within the central chamber dened by walls 39 and 40to extend the length thereof in spaced relation transversely of carrier31 Which is provided with a pair of spaced bores 47 and 48 through whichsprings 45 and 46 project. The opposite ends of the springs aresupported by shoulders 50 formed integrally with the base side wall andpositioned above bores 47 and 48 with contactor bars in the topswitching position shown in Fig. 3. Hence, the springs are arceddownwardly under pressure to bias carrier 31 into the upward switchclosing position, it being evident under the urge of spring 25 uponde-energization of solenoid 13 to position contact bars 32 in the lowerswitching position, the bias of springs 45 and 46 is increased. Uponenergization of solenoid 13 and resultant'retraction of armature 20against spring 25 to remove the bias of spring 25V spring 25 movesarmature plunger 26 downwardly toV depress carrier 31 and bars 32 fromthe heavy line position shown in Figs. 3 and .4 to the dotted lineposition shown therein to break contact points 34 and connect contactpoints 35. Since the downward urge of spring 25, with solenoid 13de-energized, is substantially greater than the counter urge oftransverse springs 45 and 46,

positive contact is` insured between bars 32 and 'lower spaced contacts35. Upon energizing solenoid 13,.springs 45 and 46 rapidly returnarmature 2t? to the Fig. l position, but since solenoid armature isdrawn upwardly against the substantial bias of helical spring 25, thetransverse carrier springs operate to aid in the smooth return ofarmature 20 without resulting chatter. The clearance between thecylindrical surface of armature 20 and the cylindrical inner wall of thechamber in which it aXially lmoves is such that as the armature israpidlyV returned to the Fig. l position, entrapped air is meteredthrough the annular channel therebetween to eifect a dash-pot action tosupplement the compression of spring to insure smooth armaturedeceleration.

Elongate springs 45' and 46 of piano wire or the like of a gage tointroduce the desired bias, positioned symmetrically of carrier 31 asshown in Fig. 2, insure horizontal positioning of carrier 31 during`depression by plunger Z6 and return, hence both connector bars 32 makeand break contact with paired contacts 34 and 35 at approximately thesame instant. The relay structure may easily be modified by eliminatingone of those two springs, such as spring 46, to provide time delaybetween the respective movements of connector bars 32 due to a resultingtilt of carrier 31 as force is applied by plunger 26. With a singlespring, such as spring 45, but of heavier gage wire, or two springs ofthe same gage projecting through the same carrier aperture 47, as shownat 45a, Fig. 6, carrier 31 is non-symmetrically biased. With the carrierand connector bars in the upper switch closing position of Fig. 3, suchnon-symmetrical bias insures irm circuit closing contact between eachbar 32 and paired contacts 34. However, upon the downstroke of thearmature, plunger 26-depresses carrier 31 at a position eccentric to theposition of applied spring bias in carrier bore 47, to tiltcarrier 31 onthe downstroke as shown in dotted Y lines, Fig. 6.

As a result, the long or right hand portion of carrier 31, as viewed inFig. 5, causes bar 32 to break from its associated contact points 34prior to a corresponding break between the corresponding bar 32 at theopposite end of the canrier and its contact points, thus introducingtimeV delay between those breaks. For the same reason, ycontact betweenthe right hand bar 32 and lower spaced contacts 35 is made prior tocorresponding contact between the left hand bar 32 and its associatedcontacts 35, hence equal time delay between breaking and making contactby each bar and its associated contacts is inherent in the eccentricallybiased modication of Fig. 5. For a. like reason, the same magnitude oftime delay is obtained on the upstroke, and while the tilt angleinvolved is the same, the left hand bar of Fig. 5, more heavily biasedsince closest to springs 45, and for that reason the trailing bar on thedownstroke is the rst to break contact on the upstroke, hence a reversalof the order of time delay occurs on the upstroke. A sequence ofoperation is thus obtained, which may be predetermined through properselection of the gage and physical prop` erties of wire-like springs 45and 46.

The improved relayv above described permits assem- 4 bly without the useof screws or rivets, since the terminal strips iind their support in thebottom wall of base 11; bars 32, interlock with opposite ends of carrier31 in a manner to be maintained in position by's'houldered portionsintegral with base 11; carrier 31`reciprocates in a guideway defined byportions molded integrally in base 11; and springs 45 and 46 rest onshoulders also formed integrally with the base sidewalls. Theconstruction thus utilizes a Aminimum. number of parts which are easilyassembled, substantially to reduce manufacturing cost. As

is well known, relays of this general type by employingr leaf or coilsprings are prone to develop chatter under certain operating conditions,due to electromagnetically induced fundamental or harmonic vibration ofthe switching elements at certain resonant frequencies. The arrangementof elements in the relay above-described is such that thecounter-biasing of the carrier spring or springs by the solenoidarmature spring in co-operation with the dash-pot effect of the;solenoid armature greatly reduces any tendency toward .eitherfundamental or harmonic vibration thereof.

I claim:

l. In an electromagnetic relay, a contact-controlling i carrier mountedfor movement between upper and lower switching positions, anelongatewi-re-like spring disposed transversely of saidcarrier with acentral portion in contact therewith, .said spring being mounted underlongitudinal distortion to urge said carrier toward an upper switchingposition, la solenoidv positioned above said carrier and having ankarmature biased downwardly to depress said carrier against the bias ofsaid transverse spring and into a lower switching position, saidvarmature being retracted upon solenoid energization to remove thedownward carrier bias with resulting movement of said carrier, underurge of said transverse spring, to the upper switching position.

2. The device of claim l wherein said carrier is'biased by a pair ofspaced elongate transverse springs disposed symmetrically of the centerof said carrier.

3. In an electromagnetic relay, two groups of spaced apart stationarycontacts having their Contact surfaces in parallel planes, each groupcomprising two pairs of spaced contacts, a movable carrier disposedtransverselyof said two groups, `a contact bar mounted at each end ofsaid carrier for alternate contacting engagement with each of said twopairs of contacts, an elongate spring mounted to be arced transverselyof said carrier with the center of said spring engaging said carrier,whereby said contact bars are spring biased to engage one set of saidpaired contacts and said Vcarrier may be moved against the bias of saidspring to cause said bars to engage the opposite set of contacts.

4. The device of claim 3 including a solenoid having an armatureengaging said carrier, spring means biasing said armature against saidcarrier under sufficient urge to overcome the counter-bias of saidtransverse spring andY move the carrier-mounted bars into engagementwith the opposite paired contacts, said solenoid, when energized,overcoming the means biasing it against the carrier to allow saidtransverse spring to bias the bars against the opposite contacts.

5. The device of claim 3 including a pair of elongate springssymmetrically spaced transversely of said carrier.

6. In an electromagnetic relay, a base, stationary spaced pairs of upperand lower contacts supported on the base, movable contact bars extendingbetween pairs of stationary contacts, a carrier connected to said bars,means forming a resilient support for the carrier and urging the contactbars toward contacting engagement with the upper stationary contacts,said means comprising a wire-like spring disposed transversely of saidcarrier with the ends thereof supported by said base and the centerthereof engaging said carrier, said spring being longitudinally arceddownwardly to bias the contact bars upwardly, spring means disposedabove said carrier and in contact therewith to urge the carrierdownwardly against thebias of said transverse spring to maintain saidbars in contacting engagement with the lower contacts, andelectro-magnetic means for overcoming, when energized, said lastmentioned spring means to allow said transverse spring to maintain saidbars in contact with said upper contacts.

7. The device of claim 6 including a pair of wire-like springs disposedtransversely of said carrier in engagement therewith at pointssymmetrically spaced in respect to the major axis thereof.

8. In an electromagnetic relay, two spaced groups of fixed switchcontacts, each group comprising two pairs of spaced contacts in parallelspaced relation to corresponding pairs in the opposite group, anelongate carrier positioned transversely of said spaced groups, meansmounting said carrier for movement in a plane normal to the plane ofsaid spaced contacts, a pair of contactor bars fixed to opposite ends ofsaid carrier in a position to be moved into contact engagement betweensaid paired spaced contacts by movement of said carrier, a wire-likespring disposed transversely of the plane of said carrier with a centralportion engaging the carrier and the ends thereof positioned to maintainsaid spring bowed downwardly and urge said contact bars into biasedengagement with one set of spaced contacts.

9. In an electromagnetic relay, a slidably mounted carrier, plural pairsof spaced contacts, Contact bars carried by said carrier for movementbetween said pairs of spaced contacts for bridging engagement therewith,spring means biasing said carrier toward engagement of said contact barswith one set of spaced contacts, said means comprising a pair ofelongate wire-like springs projected through said carrier with ends ofsaid springs anchored in a position to maintain said springs underlongitudinal arc, a solenoid having a spring-biased armature in contactwith said carrier to urge it in a direction to overcome the bias of saidwire-like springs and maintain said contact bars engaged with the otherset of spaced contacts, said solenoid, when energized, removing thedownward bias on said armature to allow the wirelike springs to move thecontact bars into engagement with said first mentioned contacts.

10. In a switch assembly, a housing of electrical insulating materialincluding side and inner walls defining two lateral and one centralchamber, a channel formed in said side and inner walls extendingtransversely of said chambers at the midpoint thereof, a switch barcarrier slidably disposed within said channel, a wire-like springmounted under longitudinal tension within said central chambertransversely of said channel with a central portion thereof in biasedengagement with said carrier to urge it upwardly of said channel, aswitch bar disposed in each of said lateral chambers and mounted toopposite ends of said carrier, upper and lower fixed sets of spacedswitch contacts positioned in said lateral chambers on opposite sides ofsaid switch bars and in the path of movement thereof, and a solenoidhaving a spring-biased armature positioned to depress said carrier andmove said switch bars against said lower switch contacts, said barsbeing moved upwardly under urge of said transverse spring to engage saidupper switch contacts upon relief of said carrier-depressing bias byenergization of said solenoid.

11. In an electromagnetic relay, a housing-like base, plural pairs ofupper and lower contacts fixed to said base, a pair of movable contactbars, each positioned to extend between pairs of fixed contacts, acarrier slidably mounted in said base for movement vertically thereofwith the ends of said carrier connected to said bars, and means biasingsaid carrier in a position for engagement of said bars in Contact withthe upper fixed contacts of said pairs, said means comprising a pair ofelongate springs disposed transversely of said carrier and symmetricallyspaced in respect to the center thereof, means connecting the ends ofsaid springs to said base at positions maintaining said springslongitudinally arced in either position of contact between said bars andsaid fixed contacts, a helical spring lfor the biased depression of saidcarrier against the bias of said transverse springs from a position ofbar contact with upper fixed contacts to a position of bar contact withlower fixed contacts, and a solenoid associated with said helical springto eliminate, when energized, the bias thereof with resultant return ofsaid contact bars to engage said upper fixed contacts.

References Cited in the file of this patent UNITED STATES PATENTS1,932,164 Petit Oct. 24, 1933 2,381,309 POWell Aug. 7, 1945 2,802,079Dllfng Aug. 6, 1957 2,834,848 Ellwood May 13, 1958

